Alphaviruses comprise a set of genetically, structurally, and serologically related mosquito-borne viruses of the Togaviridae family. Twenty-seven known viruses and virus subtypes have been classified within the alphavirus genus, eleven of which are recognized to be pathogenic to humans. Eastern equine encephalitis virus (EEEV), Western equine encephalitis virus (WEEV), Venezuelan equine encephalitis virus (VEEV), and Semliki Forest virus (SFV) are known to produce encephalitis, and infection by Chikungunya virus (CHIKV), O'nyong-nyong virus, Sindbis virus, Mayaro virus, Ross River virus, Barmah Forest virus, and Ockelbo virus result in acute onset of flu-like fever, followed by the development of a rash and arthritis. The evolution and spread of alphaviruses into new geographic areas, and the disease severity resulting from alphavirus infection present a serious public health issue in the absence of a vaccines or anti-viral therapies.
Flaviviruses comprise a set of genetically, structurally, and serologically related mosquito-borne or tick-borne viruses of the Flaviviridae family that also pose current or potential threats to global public health. Yellow Fever Virus (YFV), Dengue Virus (DENV), Japanese Encephalitis Virus (JEV), Tick-Borne Encephalitis Virus (TBEV), and West Nile Virus (WNV) result in a range of symptoms ranging from flu-like symptoms such as fever, chills, and vomiting to severe symptoms such as muscular rigidity, photophobia, hyperexcitability, abnormal tremors and movements, incoordination, paralysis, sensory loss, convulsions, respiratory dysfunction, and severe hemorrhages. Like other arthropod-borne viruses, the evolution and spread of flaviruses into new geographic areas, and the disease severity resulting from flavivirus infection present a serious public health issue in the absence of a vaccines or anti-viral therapies.